Lock cylinder assembly



Feb. 6, 1968 JOHNSTONE I 3,367,156

LOCK CYLINDER AS SEMBLY Filed May 25, 1966 2 Sheets-Sheet 1 INVENTOR.

ATTORNEY Feb. 6, 1968 T. H. JOHNSTONE LOCK CYLINDER ASSEMBLY 2 Sheets-Sheet 2 Filed May 25, 1966 ATTORNEY United States Patent 3,367,156 LOCK CYLINDER ASSEMBLY Theodore H. .Iohnstone, New Baltimore, Mich, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed May 25, 1966, Ser. No. 552,974 9 Claims. (Cl. 70366) This invention relates to lock cylinder asemblies and more particularly to side bar type lock cylinder asemblies.

It has heretofore been proposed to provide side bar type lock cylinder assemblies with tumblers pivoted to a rotatable plug. When the proper key is inserted within the plug, the tumbler notches are aligned with the side bar and permit the side bar to move out of locking relationship with the lock casing. The side bar, the plug, and the proper key can then be rotated relative to the lock casing.

While the lock cylinder assembly of this invention is of the pivoted tumbler type, it differs from such other assemblies in several important features. One feature is that the tumblers are stationary and encircle the plug. The tumblers are generally crescent shaped and are pivoted adjacent one end thereof to the casing as close as possible to the outer surface thereof. The other notched ends of the tumblers are located the maximum possible linear distance from the pivoted ends thereof. The tumblers are engageable intermediate the ends thereof by the proper key so as to be moved about their pivoted ends. The multiplication factor is increased to the maximum so that movement of the tumblers about their pivoted ends results in approximately twice as much movement of the tumblers at their notched ends. The side bar is also mounted on the casing so that only the plug and the proper key rotate when the lock is placed in unlocked condition.

By having the tumblers of the maximum possible effective length between their pivoted ends and their notched ends, freeze problems are reduced to a minimum since a maximum lever arm between the pivoted ends of the tumblers and their key engageable portions is obtained. Additionally, the plug can be made of a reduced size and space left between the plug and the tumblers to further decrease freeze problems.

Another feature is that a frangible connection is provided between the plug and a driver which is also rotatably mounted on the casing and connected to whatever member is to be operated by the lock cylinder assembly. This connection'is weaker than the interlocking connection between the side bar and the plug in the locked position of the assembly. Thus, if a tool is inserted in the plug and the plug forcibly rotated, the frangible connection will break and free the plug from the driver to prevent operation of the driver operated member. The plug can easily be removed and replaced without replacing the entire assembly.

The primary object of this invention is to provide an improved side bar lock cylinder assembly of the pivoted tumbler type. Another object of this invention is to provide an improved side bar type lock cylinder assembly of the pivoted tumbler type wherein the tumblers and side bar are mounted on the casing, and the plug and proper key rotate relative to the tumblers and side bar. A further object of this invention is to provide a side bar type lock cylinder assembly having a plug and a driver adapted to be connected to a member to be operated, with a frangible connection being provided between the driver and plug of less strength than the locking connection between the side bar and casing to prevent movement of the driver should the plug be forcibly rotated.

These and other features of the invention will be readily apparent from the following specification and drawings wherein:

FIGURE 1 is an elevational view of a lock cylinder assembly according to this invention;

FIGURE 2 is an enlarged sectional view taken generally along the plane indicated by line 2-2 of FIGURE 1;

FIGURE 3 is a view taken generally along the plane indicated by line 33 of FIGURE 2;

FIGURE 4 is a sectional view taken generally along the plane indicated by line 4-4 of FIGURE 3;

FIGURE 5 is a view similar to FIGURE 3 with the key removed; and

FIGURE 6 is a view taken generally along the plane indicated by line 6-6 of FIGURE 5.

Referring now particularly to the drawings, a lock cylinder assembly 10 according to this invention includes an outer casing 12 which is adapted to be fixedly mounted in any suitable manner on a support. The casing 12 includes an outer counterbored portion 14 which rotatably receives a like shaped annular outer portion 16 of a plug 18. The counterbored portion 14 of the casing 12 opens into a bore portion 20 of lesser diameter which terminates in an inner counterbored portion 22. The portion 16 of the plug 18 is joined to an inner annular portion 24 of the plug by a pair of longitudinally extending webs 26, the inner surfaces of which are shaped to provide a key receiving slot 28 adapted to receive a double bitted key 30. The portion 24 of the plug is rotatably received within the counterbored portion 22 of the lock casing.

A conventional shutter 32 is pivotally mounted on a pin 34 which is staked within openings in the outer key receiving bore 36 of plug portion 16. A coil torsion spring 38 engages both the shutter 32 and a sealing washer 40 to bias the shutter to a closed position wherein it closes the key receiving slot42 of the washer 40, as shown in FIGURE 5. The washer 40 is located within a counterbored portion 44 of bore 36 and is located against axially outward movement by a cap 46 which surrounds an outer annular flange portion 48 of the casing and is secured thereto by a number of bent tabs 50. The cap 46 is provided with a key receiving opening 52 to provide access therethrough for the key'30. A number of compression springs 53 seat in bores of plug portion 16 and engage washer 40.

The lock casing 12 is provided with a number of like transverse tumbler receiving slots 54, each of which re ceives a generally crescent shaped tumbler 56. One apertured end of each of the tumblers is pivotally mounted on a pin 58 which extends through the lock casing webs 60 and is secured in bores in the casing to each side of the outer slots 54. A spring 62 has its base portion staked within a slot 64 of the casing 12 and includes a plurality of laterally extending spring fingers 66 which are respective to each of the tumblers 56 and are located within the slots 54. The outer reversely bent ends 68 of these spring fingers engage respective tumblers 56 to bias the tumblers counterclockwise about the pivot pin 58. Each of the tumblers includes a key engageable node 70 intermediate the ends thereof. The other end of each of the tumblers 56 is provided with a generally V-shaped notch or groove 72 which opens to an edge portion 74 of the tumbler. The notches or grooves are spaced along the edge portion 74 depending on the key code of the assembly.

As best shown in FIGURES 4 and 6, the casing 12 is provided with a longitudinal groove 76 which opens to bore portion 20 and slidably receives a generally V-shaped side bar 78. One end of the side bar is slidably mounted in a groove 80 of casing 12 and the other end includes a locking lug 82 which is slidably mounted in a groove 84 of casing 12.

A spring 86 has its base portion staked within a groove 88 of the casing 12 and includes a pair of spring fingers 90 which engage the side bar 78 to bias the side bar inwardly of the casing 12. Spring 86 is located within an outer partial circumferential groove 92 of casing 12.

A driver 94 is rotatably mounted within a counterbored portion 96 of the casing 12 which opens to the bore portion 20 and groove 84. The driver is adapted to be connected to whatever member is to be operated by the lock cylinder assembly. The driver includes an internal annular groove 98 which is of the same radial depth throughout except for a radially and axially opening locking notch 100 which is of suflicient annular extent to receive the locking lug 82 of side bar 78.

An extension 102 of the plug 18 extends outwardly through an opening 104 in an annular flange of the casing 12 which defines a wall of the bore portion 22. Extension 102 is provided with a radially extending key 106 which is received within a keyway 108, FIGURE 2, of the driver 94 to key the driver to the plug for rotation therewith. The key and keyway provide a frangible connection between the plug and the driver. This connection is of less strength than the connection between the driver and casing 12, which is provided by the locking lug 82 of the side bar being received within the groove 84 and notch 100, as will be further described.

When the proper key is not inserted within the plug 18 as shown in FIGURES 5 and 6, the fingers 66 of the spring 62 bias the tumblers 56 counterclockwise until the nodes of the tumblers seat on one of the webs 26 of the plug. This forces the side bar 78 outwardly within the groove 76 as the side bar is cammed out of the notches 72 and engages the edge portions 74 of the tumblers. The spring 86 is weaker than the spring 62 to permit the turnblers to cam the side bar outwardly when the key is removed. As the side bar 78 is cammed outwardly, the locking lug 82 moves radially outwardly within groove 84 and within the locking notch 100 of the driver to thereby lock the driver 94 to the casing 12.

If a tool or unauthorized key is inserted in the plug 18 and the plug forcibly rotated, the key 106 will break to prevent rotation of the driver 94. This will occur since the connection provided by the key 106 and keyway 108 is of less strength than the connection provided by the lug 82 being received within the slot 84 of the casing and the locking notch 100 of the driver. Thus, any unauthorized operation of the member to "be operated by the lock cylinder assembly is effectively prevented. The plug 18 can be easily replaced by removing the cap 46, inserting a new plug, and thereafter replacing the cap.

When a proper key is inserted within the plug 18, the teeth of the key engage the nodes 70 of each of the tumblers to swing the tumblers clockwise about the pin 58 until the openings 72 thereof are aligned as shown in FIGURE 4. The spring 86 can thereby cam the side bar 78 inwardly of the lock casing to its unlocked position, as shown in FIGURES 3 and 4, wherein the locking lug 82 is located radially inwardly of the notch 100 so that the plug 18, the key, and the driver 94 can rotate within the tumblers and casing and operate whatever member is to be operated.

It will be noted that the pivoted ends of the tumblers are located as closely as possible to the outer surface of the casing 12 and likewise the notched ends of the tumblers are located as closely as possible to the outer surface of the casing 12 generally opposite the pivoted ends of the tumblers. Thus, the maximum possible linear distance between the pivotal axis of the tumblers and the base of the notches 72 is obtained. It will also be noted that the nodes 70 are located generally intermediate the ends of the tumblers. Thus, when the proper key 30 is inserted, there is approximately twice as much movement of the tumblers at their notched ends than at their nodes. This is a very distinct advantage since it increases the freeze resistance of the lock to the maximum. The multiplication factor can be changed by changing the relationship of the pivot axis of the tumblers to the nodes 70 or the key.

It will also be noted that the crescent shaped tumblers generally surround the Webs 26 of the plug and that as much space as posible is provided between the tumblers and webs. This permits easy flow of water out of the lock cylinder assembly and also permits expansion of any freezing water within the assembly without freezing the parts together.

Thus, this invention provides an improved lock cylinder assembly.

I claim:

1. A lock cylinder assembly comprising, in combination, a casing structure, a key receiving plug, means rotatably mounting said plug within said casing structure, a plurality of tumblers traversing said plug, said tumblers each having one end thereof located to one side of said plug and the other end thereof located to the other side of said plug, means rotatably mounting said tumblers adjacent said one ends thereof on said casing structure, each of said tumblers including a side bar receiving opening adjacent the other end thereof, each of said tumblers including a node intermediate the ends thereof engageable by a proper key inserted within said plug to move said tumblers to unlocked position wherein said side bar receiving openings are successively aligned, a side bar mounted on said casing structure for movement between locked and unlocked positions with respect to said plug, said side bar having means locking said plug to said casing structure in the locked position, said side bar being received within said tumbler openings in the unlocked position thereof and of said tumblers to free said locking means on said side bar from said plug for rotation of said plug and the key inserted therein as a unit relative to said casing structure, said tumblers and said side bar.

2. The combination recited in claim 1 wherein the distance between the pivotal axis of said tumblers and said other ends thereof is generally twice the distance between the pivotal axis and the nodes thereof so that movement of said tumblers at their other ends is multiplied approximately twice than at their nodes.

3. The combination recited in claim 1 wherein said casing structure includes a generally annular member provided with a plurality of radially outwardly opening slots therein, each slot receiving a respective tumbler, said tumblers being rotatably mounted for movement within said slots by means of a common mounting member located as closely as possible to the outer surface of said annular member to obtain the maximum possible distance between the pivoted one ends of said tumblers and the other ends thereof.

4. The combination recited in claim 1 wherein said plug includes annular inner and outer portions rotatably mounted within said casing structure and an intermediate web portion symmetrical about a central axis and receiving the key.

5. The combination recited in claim 4 wherein said nodes are engageable with said web portion of the plug when the key is withdrawn to locate said tumblers in locked position wherein said openings are misaligned.

6. The combination recited in claim 1 wherein each of said tumblers includes a cam surface adjacent the opening therein engageable with said side bar under a resilient biasing force when said key is removed to cam said side bar to locked position.

7. The combination recited in claim 6 including individual spring means biasing each of said tumblers to the locked position thereof wherein said openings are misaligned, spring means biasing said side bar toward said unlocked position thereof, said tumbler spring means being of greater force than said side bar spring means to cam said tumblers past said side bar and move said side bar out of said openings and into engagement with said cam surfaces to move said side bar to locked position.

8. The combination recited in claim 1 including a driver rotatably mounted within said casing structure, frangible means interconnecting said driver and said plug for co,-

rotation as a unit with the proper key, and interlocking means between said driver and said side bar when said side bar is in locked position, said interlocking means being of greater strength than said frangible interconnecting means whereby forcible rotational movement of said plug by an unauthorized means will result in breaking of said frangible means without operation of said driver.

9. The combination recited in claim 1 wherein said casing structure includes a longitudinal slot receiving said side bar, said plug including a driver secured to said plug for rotation therewith, said driver including an annular groove provided with a portion of greater radial depth, said side bar including a lug received in said portion of greater radial depth of said driver in said locked position References Cited UNITED STATES PATENTS Ritzert 70-366 Heyer 70-422 XR Fitzgerald 70422 XR Jacobi 70366 Young et al. 70366 Willett et a1 70-666 XR Spain 70-366 X Johnstone 70364 MARVIN A. CHAMPION, Primary Examiner.

of said side bar to lock said driver and plug to said casing 15 PERRY TEITELBAUM, Assistant Examinerstructure. 

1. A LOCK CYLINDER ASSEMBLY COMPRISING, IN COMBINATION, A CASING STRUCTURE, A KEY RECEIVING PLUG, MEANS ROTATABLY MOUNTING SAID PLUG WITHIN SAID CASING STRUCTURE, A PLURALITY OF TUMBLERS TRAVERSING SAID PLUG, SAID TUMBLERS EACH HAVING ONE END THEREOF LOCATED TO ONE SIDE OF SAID PLUG AND THE OTHER END THEREOF LOCATED TO THE OTHER SIDE OF SAID PLUG, MEANS ROTATABLY MOUNTING SAID TUMBLERS ADJACENT SAID ONE ENDS THEREOF ON SAID CASING STRUCTURE, EACH OF SAID TUMBLERS INCLUDING A SIDE BAR RECEIVING OPENING ADJACENT THE OTHER END THEREOF, EACH OF SAID TUMBLERS INCLUDING A NODE INTERMEDIATE THE ENDS THEREOF ENGAGABLE BY A PROPER KEY INSERTED WITHIN SAID PLUG TO MOVE SAID TUMBLERS TO UNLOCKED POSITION WHEREIN SAID SIDE BAR RECEIVING OPENINGS ARE SUCCESSIVELY ALIGNED, A SIDE BAR MOUNTED ON SAID CASING STRUCTURE FOR MOVEMENT BETWEEN LOCKED AND UNLOCKED POSITIONS WITH RESPECT TO SAID PLUG, SAID SIDE BAR HAVING MEANS LOCKING SAID PLUG TO SAID CASING STRUCTURE IN THE LOCKED POSITION, SAID SIDE BAR BEING RECEIVED WITHIN SAID TUMBLER OPENINGS IN THE UNLOCKED POSITION THEREOF AND OF SAID TUMBLERS TO FREE SAID LOCKING MEANS ON SAID BAR FROM SAID PLUG FOR ROTATION OF SAID PLUG AND THE KEY INSERTED THEREIN AS A UNIT RELATIVE TO SAID CASING STRUCTURE, SAID TUMBLERS AND SAID SIDE BAR. 